GAINS UP TO: +79 horsepower +96 lb-ft torque 24% quicker 0-60 mph 20% better mileage
GM Motorhome Power PowerPack ® and Stinger ® Systems for GM 7.4L (454) Class-A Motorhomes
G A L E
B A N K S
E N G I N E E R I N G
It’s all about airflow “Every aspect of the final design was carefully engineered for optimum improvement of the engine’s ability to breathe.” — MOTORHOME
1982-95 MOTORHOMES Banks PowerPack system eliminates the “sins” of the factory – intake and exhaust restrictions – and replaces them with a suite of components that allow your engine’s full potential to be realized. PowerPacks for throttle-body-injected (TBI) engines typically include: Banks Ram-Air intake system with Super-Scoop air inlet and ducting, cast-aluminum airfilter cover, lifetime, high-flow air cleaner and service kit. On the exhaust side, Banks stainless TorqueTube exhaust manifolds combine with Banks stainless Dynaflow muffler, and constant-diameter, stainless Monster exhaust with 3.5-inch* tailpipe and a polished stainless tailpipe tip. Heat shielding included as necessary. *For carbureted motorhomes, Banks offers a choice of stainless or aluminized steel 3-inch exhaust system.
Shown: PowerPack system for EFI (TBI) models, with optional extension kit for longer wheelbases.
“ Knowing Gale,there’s something big stuffed under the hood. His reputation for sweetening horsepower with his innovative engine applications has attracted individuals and corporations. Banks owns the leading-edge in technology these days.” — MOTORWEEK
Shown: PowerPack system for Vortec models (P-30 chassis, passenger-side tailpipe exit).
1996-00 VORTEC MOTORHOMES differ from pre -1996 systems: Banks’ huge, stainless Dynaflow muffler is customengineered with a 3.5-inch outlet to provide the freest possible flow through Vortec exhausts. Banks PowerPack systems for Vortecs also include: Banks Ram-Air intake system with Super-Scoop air inlet and ducting, lifetime, high-flow air cleaner and service kit, stainless TorqueTube exhaust manifolds and constant-diameter, stainless Monster 3.5inch tailpipe with a polished stainless tailpipe tip. Left or right exit option. Heat shielding included as necessary.
T E S T
Although GM’s 7.4L powerplant ceased production in 1999, its ruggedness promises faithful service for another generation on the highways. Thanks to its affordability and reliability, the chassis remains a popular choice among Class-A motorhome owners, despite the desire for bolder performance.
Stock Performance During a driving analysis of a stock 7.4L TBI test vehicle, Banks engineers recorded that power fell off significantly sooner than the factory-specified 3600-rpm peak. Engineering manager Peter Treydte commented that after 3300 rpm, “It feels like half the engine just disappears!” Banks DynaFact instrumentation confirmed that the engine topped out at only 177 hp @3300 rpm. At the critical upshift point, output stalled at a weakly 146 hp, causing power-fades on the grade as the engine struggled to the shifts. Full-throttle driving gave the transmission a workout as it searched for the power-and-gear combo to get the rig uphill.
Report from independent road tests: “ Back on the road, Banks PowerPack did everything Gale said it would: most noticeably, increased gas mileage and power. Now we’re able to go up most hills in high gear, with no loss of speed.” — OUTDOOR NEWS NETWORK
“ The improvement in all categories of testing was impressive. Picking up 2.85 mpg and 11 mph while pulling the grade is significant.” — MOTORHOME
Merging attempts from 0-to-60 mph required 1325 feet — a lot longer than standard freeway onramps. On the road, the coach required a casual 12.7 seconds to “accelerate” from 40-to-60 mph. With such meager power, any thought of moving out and around a farm vehicle in front was just a “passing fancy” that could not be safely tested. The engine ran far less efficiently than it should, adding to wear-and-tear. Mileage suffered, averaging well below 7 mpg. Operating at moderate speeds on a temperate day, the exhaust gas temperature (EGT) in the manifolds exceeded 1550°F — hot enough to start cracking some bolts.
Power Inhibitors What causes a stalwart big-block to fall on its face like that? Simply put, the muscular big block was gasping for air. The stock intake set-up prevents the engine from getting anything near its capacity of ram-air. Suction-loss tests indicate the factory’s puny induction parts produce 17.0 in/H2O vacuum; that limits power production and wastes fuel. Exhaust backpressure caused by the factory’s restrictive muffler and crudely bent tailpipe maintained a 7.5-psi crescendo. No wonder it was sluggish when they put the hammer down! Factory-bred airflow restrictions put the brakes on power; Banks PowerPack system releases it.
Performance Test Weight: 16,560 lbs.
R E S U L T S
The Banks team invested many months to uncover the true potential of GM’s big iron. “We analyzed the engine’s output data, logging what it was doing 20 times a second, to let us know what direction we should be going,” said Gale Banks. The first order of business is to mildly supercharge the engine with ram-air. Banks Ram-Air intake includes the Super-Scoop inlet, to swallow up more ram-air and feed it to the engine through Banks 4-inch ducting. Banks lifetime Ram-Air filter replaces the paper element and reduces air-cleaner suction by 86%. Banks cast aluminum housing encourages the ram-air’s express trip into the combustion chambers, where power is made. Banks stainless TorqueTube manifolds actually pull exhaust from the engine, producing gains that multiply torque output as much as 150%. Banks combination of the stainless, acoustic-tuned Dynaflow muffler and Monster tailpipe slash exhaust backpressure by 90%.
“ Peak numbers tell just part of the story. The Banks PowerPack broadened the total range.” —COAST TO COAST
V-8 power unbound Throttle response is the first clue that the motorhome has been set free. The coach accelerates from 40-to-60 mph 26% faster and cuts a football field off the 0-to-60 mph distance. Onramps and passing are no problem now! PowerPack moves the horsepower peak from 177 hp @3300 rpm to 233 hp @4000 rpm, so there’s plenty of stuff to march the rig strongly to the 4300-rpm upshift. At the downshift, Banks has +81 more lb-ft of torque to muscle heavy loads onward and upward.
Rear-wheel Torque (lb-ft)
“Most impressive is an increase in max speed on a 6% grade from 57 mph to 68 mph, in a higher gear” said Engineering manager Peter Treydte. “In a motorhome with massive frontal area, this is power that can be felt.” As you revel in top gains of +79 hp and +96 lb-ft, be sure to smile politely going past those fancy diesel pushers. All this power and torque is like money in the bank — there to draw from whenever you want it, earning durability and mileage “interest” every mile. PowerPacks thrive on regular octane and improve fuel economy up to 20% in pre-Vortecs; 10% in Vortec-equipped coaches. PowerPacks drop EGTs hundreds of degrees, prolonging engine life. All Banks systems meet or exceed emissions requirements in 50 states.
24.2 18.4 0-60 MPH TIME (SEC)
24 r! Shorte
1400 1120 840 560 280
1325 1008 0 0-60 MPH DISTANCE (FT)
10.4 7.8 5.2 2.6 0.0
12.7 9.4 40-60 MPH TIME (SEC)
9.0 7.5 6.0 4.5 3.0 1.5 0.0
6.9 8.3 FUEL ECONOMY (MPG)
70 60 50 40 30 20 10
57 68 0 HILL-CLIMB SPEED (MPH)
If your needs don’t require the mega-power of Banks PowerPack, Stinger is the economical alternative. Best gains of +58 hp and +64 lbft (TBI) or +48 hp and +49 lb-ft (Vortec) supply the muscle to handle many jobs. Banks constructs Stinger systems just like their PowerPack counterparts, but leaves out the stainless TorqueTube exhaust manifolds — the airflow improvements provide better mileage and prolong engine life. Shown: Stinger system for Vortec (P-30 chassis; driver-side tailpipe exit)
BANKS RAM-AIR This cut-away compares Banks 1990-95 cast Hi-Rise filter and housing (left) to the stock lid. Its sloping sides and greater volume optimize airflow. Vortec motorhomes utilize Banks Ram-Air assembly with lifetime, high-flow air cleaner and service kit.
DYNAFLOW Banks built a stainless-steel giant among mufflers. The Dynaflow’s broad, acoustic-tuned chambers and dual-inlets flow 503 cfm @1in/Hg backpressure — a 74% improvement over the factory muffler’s 289 cfm. You get a commanding exhaust grumble that pronounces its power without disturbing your conversation.
17.0 in/H2O 2.4 in/H2O
AIR CLEANER VACUUM @ equal airflow
Stock muffler (Vortec)
BANKS RAM-AIR ™ INTAKE Banks’ intake improvements take advantage of the natural supercharging effect ram-air provides. (If you’ve ever stuck your hand out the window at 60-mph and felt the force working against it, you know what ram-air is.) Banks behind-the-grille SuperScoop® is 156% larger than the stock piece to harness more ram-air, separate out debris and rainwater and send the ram-air through a 4inch duct to the high-flow, lifetime Banks RamAir filter. That packs cool, dense ram-air into your engine, increasing power and efficiency. DYNAFLOW® MUFFLER Banks mufflers are designed with internal baffling or chambers to achieve very low restriction and freely dispel exhaust gases. Banks acoustically tunes out the annoying resonance that comes down the pipe from the engine, and replaces it with an authoritative, yet civilized, exhaust note. Constructed of stainless steel, Dynaflows are virtually impervious to cracking or blowing out. Equipped with formed-metal heat shielding as needed. 8.0
Banks Dynaflow (Vortec)
MONSTER® EXHAUST Banks replaces the restrictive factory piping with a stainless, 3.5inch* constant-diameter tailpipe for maximum flow potential — and tops it off with a colossal 4-inch* polished-steel tailpipe tip for a handsome finishing touch. Left- or right-exit for Vortec models. *Note: Stinger systems for Pre-Vortec (‘95-earlier) models include a 3-inch aluminized tailpipe and 3.5-inch polished tip.
TORQUETUBES Banks bulletproof torque monsters are streamlined, tubular manifolds constructed of heavy-wall stainless steel. The ultra-thick, 5⁄8 -inch flanges are machined flat to mount without gaskets that can blow out. Accommodates your spark-plug heat shields, so there’s no need for expensive plug wires.
9e0tt% er! B
7.50 psi 0.75psi
EXHAUST BACKPRESSURE @ equal airflow
TORQUETUBE® MANIFOLDS are the industry’s only exhaust manifolds tuned to take full advantage of motorhome power. “Others’ exhaust manifolds have short tubes designed for the higher rpm range typically used in race-type applications,” Banks chief designer Bob Robe explains. “This is of little value on a motorhome. We use much longer, somewhat smaller diameter, primary tubes. This and our exclusive high-velocity collector literally suck the exhaust out of the engine — boosting torque for stump-pulling guts.” TorqueTubes run your exhaust 150 to 200°F cooler.
Test vehicle: 31-foot GM 7.4L (454-ci) motorhome, P-30 chassis, throttle-body injected Vortec note: Gains produce final results equivalent to TBI Power and Performance data
POWER @ REAR WHEELS Horsepower, best gain Horsepower, peak-to-peak Horsepower gain @ upshift point at wide open throttle
Torque, best gain (lb-ft) Torque, peak-to-peak (lb-ft) Torque gain @ downshift point (lb-ft)
Exhaust backpressure (psi)
Air cleaner vacuum (in/H 2O)
Acceleration, 0-60 mph, Time (sec)
Acceleration, 0-60 mph, Distance (ft)
Passing, 40-60 mph, Time (sec)
at wide open throttle
Exhaust gas temperature (°F) Total system @ equal airflow at equal horsepower
Maximum speed, hill-climb (mph) 6% grade
Fuel economy (mph)
Over 7,000-mile test route
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©2000 Gale Banks Engineering. All rights reserved. This material is for personal use only. Re-publication and re-dissemination, including posting to news groups, is expressly prohibited without the prior written consent of Gale Banks Engineering.
Gale Banks Engineering • 546 Duggan Avenue • Azusa, CA 91702 • (626) 969-9600 • Fax (626) 334-1743 Product Information & Sales (800) 438-7693 • Customer Support (888) 839-5600 • Installation Support (888) 839-2700 • Mon-Fri 6am-6pm; Sat 7am-1pm; PST